Brachychiton Pests

Weevils/Psyllids

Weevils and psyllids attack the bottle tree in its native habitat. Weevils are grub-like creatures that tunnel through the wood or attack seedpods. Chemical controls are ineffective against wood-boring weevils, and not necessary against pod weevils because seed pods can be protected by covering them with plastic. Two psyllid species attack bottle trees by sucking sap out of the trees. The Kurrajong star psyllid nymph has a red stripe that runs from its head to its abdomen. The adult form is green with dark stripes. The Kurrajong psyllid nymph is yellow and brown and the adult is reddish-brown with dark markings and a black head. Natural predators normally keep psyllid populations in check.

Other native pests of the bottle tree include the Kurrajong leaf tier and the Kurrajong pod beetle in Australia. The Kurrajong leaf-tief is a green caterpillar that grows to be about an inch long. Although caterpillars can defoliate trees, treatment isn't necessary since trees recover over the winter. Kurrajong pod beetle larvae are long, reddish-brown insects that grow to be about 2/10 inch long. They feed on the seed pods but, since germination isn't affected, it's not necessary to control them.

Both the nymphs and the adult giant whitefly damage bottle trees by sucking the sap out of the leaves. Large numbers of whiteflies weaken trees by interfering with its ability to acquire water and nutrients. Giant whiteflies also excrete honeydew, a sticky substance that builds up the leaves and attracts black sooty mold. The sooty mold fungus interferes with the leaf's ability to do photosynthesis. Whitefly nymphs resemble scales with their small, oval bodies. They don't have wings and seem not to have legs. Adults look like small moths. Giant whiteflies grow to be about 3/16 inch long and leave wax deposits on leaves when they're walking on them. Control whitefly infestations by washing insects off the leaves with a strong spray of water. Infested leaves can also be removed.

Twospotted spider mites also feed on bottle trees. These tiny bugs are only 1/50 inch long and have oval bodies that can be brown, orange, green or translucent in color. The large, dark spots are actually areas where masses of body waste can be seen through the transparent body. Like their spider cousins, spider mites have eight legs. Spider mites damage bottle trees by feeding on the plant sap in the leaves. Symptoms include the appearance of light dots on the leaves, followed by yellowing and leaf drop. Spider mites make fine webbing, which is usually visible on the leaves and twigs. Spider mites are usually controlled by natural enemies like ladybird beetles, predatory mites and minute pirate bugs. Control mites by knocking them off plants with a strong stream of water or use insecticidal soaps and oils.